yashsingh1/xdaforums huggingface dataset:
[Nook Color General] Socket:
Update: I migrated my 8GB card content over to the Sandisk 32G Ultra UHS-1, and it definitely runs much faster than the 8 GB card, as one would expect given the much higher 4k random write results.

However this card, when running CM10 from it, either won't boot properly, or if it does, the session doesn't last long before spontaneously rebooting (probably due to kernel panic). I even rebuilt it from the ground up (the first migration was by cloning the disk image). Both attempts resulted in unstable booting and running. When I switch back to the old 8GB card with the same content on it, CM10 is stable and fine.

So it unfortunately looks like this model of card does have a reliability issue, and I didn't have to wait 2 months either.. it was having issues immediately on the first day. If I can find a Windows application that lets me "realign" ext partitions, I'll make another attempt at this. But if not, this card is getting returned.
[Nook Color General] leapinlar:
Just to remind folks, he's running on an HD+ so what he said about instability may not apply to Nook Colors.

Sent from my Nook HD+ running CM10 on Hybrid SD
[Nook Color General] Socket:
Right, this was testing on my Nook HD+.

However as it turns out, I also have a Nook Color which I set up a few months ago for dual boot, with CM7 on external SD (another 8GB slow card). It's stable using that 8G card.

I think I'll clone that card content over to this 32G Sandisk and see if the 32G card causes instability on a Nook Color/CM7 also. Stay tuned...
[Nook Color General] Socket:
Update:

I cloned my Nook color 8g Cm7 ext SD card over to this 32G Sandisk (I didn't extend any partitions, so it's just got the same 8GB of partitions on it) and tried it in the Nook color.

No dice - totally unstable. Couldn't even boot. I would get the "Cyanogen.. Loading.." boot splash screen for 30 seconds, then it would go dark, then repeat, then go dark, then stayed dark permanently. I manually rebooted.. .same thing 2nd time. Popped the old 8GB CM7 card back in, and it booted fine.

So at this point I think I can definitively say that this Sandisk 32GB Ultra UHC-1 Class 10 card is total crap, both for Nook Color w CM7 on SD, and Nook HD+ with CM10 on SD.
[Nook Color General] tonestertm:
Sorry, I don't think you can "definitively" say anything about that card with Nook Colors yet. If you start from scratch with proper image, partitioning and an MD5 checked ROM, (no cloning, and only migrating data) and it still won't go, THEN you can write it off. :)
[Nook Color General] Socket:
I've put all the effort into the nook color side that I planned to. I'm satisfied with my conclusion as far as my needs go.

If someone else wants to run an experiment on nook color rebuilding this particular model card from scratch instead of cloning, they are welcome to do so.
[Nook Color General] leapinlar:
You must have a bad card. I use these on my Nook Colors all the time with no issues.

Sent from my Nook HD+ running CM10 on Hybrid SD
[Nook Color General] wrevilo:
I hope to get my sister's unused Nook Color to play around with and will stick CM10 upon it. I've benchmarked a couple of micro SD cards I have in other devices - an 8Gb Samsung in my Nook Simple Touch and a 32Gb Sandisk in my Sandisk Sansa Clip+. Here are the results:

Both tested via a Samsung adapter in my laptop's SD card reader.

As you can see the Sandisk dominates the random write tests. I think I will pick up a 32Gb Sandisk or Samsung, test them and if the random write is significantly worse than my existing Sandisk I will swap some data around to get the best card for the job in the Nook Color.
[Nook Color General] Socket:
Be careful, my 32GB Sandisk Ultra (class 10) is unstable. I recall reading in this forum that others had stability issues with Sandisk cards over 16 GB.

I just received two Sandisk 16 GB Class 4 cards and am in the process of burning CM 10 to one of them. Here are the CrystalDiskMark stats for one of them:

-----------------------------------------------------------------------

CrystalDiskMark 3.0.2 x64 (C) 2007-2013 hiyohiyo

Crystal Dew World :

http://crystalmark.info/

* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

Sequential Read : 19.373 MB/s

Sequential Write : 5.863 MB/s

Random Read 512KB : 19.030 MB/s

Random Write 512KB : 3.376 MB/s

Random Read 4KB (QD=1) : 4.323 MB/s [ 1055.4 IOPS]

Random Write 4KB (QD=1) : 1.471 MB/s [ 359.2 IOPS]

Random Read 4KB (QD=32) : 4.542 MB/s [ 1109.0 IOPS]

Random Write 4KB (QD=32) : 1.333 MB/s [ 325.3 IOPS]

Test : 50 MB [M: 0.0% (0.0/14.8 GB)] (x5)

Date : 2013/03/10 12:28:34

OS : Windows 7 Home Premium Edition [6.1 Build 7600] (x64)
[Nook Color General] wrevilo:
OK so I received my 32GB Sandisk Ultra class 10 card and have tested it:

It is now in the NC and will be used as a media drive, as I installed CM10 to the internal memory. Shame it's not as fast as the Samsung for sequential writes, which would have been better for writing files over from my desktop.
[Nook Color General] DonEdwards:
An answer, and a surprising slight problem...

Answer first. A while back there was some wondering why it's small-block random *write* speed that seems to be critical, but random *read* speed doesn't seem to matter so much. The theorizing was that it's plenty fast enough in all cases, and maybe if we found a device where random read speed is slower than random write speed, we could draw some better conclusions.

Well, I found such a device.

4K random, Q=1: read 0.413, write 1.572

4K random, Q=32: read 0.903, write 1.806

Those random read speeds are about the worst we've seen in this thread. While the random write speeds are near the top.

I don't know how well this device would work for Android, but it's just fine as the boot (and primary storage, and swapfile) device for Windows 7 64-bit. And it works pretty good for Linux too, according to quite a few people.

Yep, it's the HD (complete with spinning disk) in my laptop.

A Toshiba USB drive is essentially the same speed at Q=1, but about 2/3 that speed at Q=32. So these numbers are probably typical of HDs of similar age.

So, it looks like "everything out there is plenty fast enough in that category" is almost certainly the correct answer.

Full results with 5 repetitions, just for the sake of completeness:

Samsung HM250HI 250GB hard drive, internal

Sequential read 69.43 write 67.54

Random512K read 30.09 write 41.70

Random4K,Q=1 read 0.413 write 1.572

Random4K,Q=32 read 0.903 write 1.806

Toshiba 500GB USB3 drive

Sequential read 29.36 write 18.53

Random512K read 19.92 write 23.50

Random4K,Q=1 read 0.427 write 1.362

Random4K,Q=32 read 0.638 write 1.355

----

Now for the surprising slight problem: I've observed that CrystalDiskMark 3.0.2 (can't comment on any earlier version) does NOT average the results of multiple tests. It shows the best single-test result. Next time you're running it, actually sit and watch what it puts in the result boxes... in each box it puts the result of EACH test run as it finishes, until it finishes the last of however-many-you're-doing when it puts up either the highest number it has shown for one of this batch or a new number that is even higher.

If it were averaging the results, then the more times you ran the test the more *typical* and *reliable* your result would be. But with it instead showing the best result, the more times you run the test the more *exceptional* and *unreliable* your result is likely to be.

In the times I was watching it, I frequently saw that the lowest result in a 5-repetition cycle would be around half of the final result. (And of course I never saw a result higher than the final result, or I wouldn't be talking about this.) So there's obviously plenty of room for exceptional results.
[Nook Color General] Agwalters:
Thank you!

Thank you for this post. I had rooted my Nook color using a Sandisk 32 GB class 10 SD card only to find the delay time intolerable. Used 8GB class 2 and the Heavens parted! Now running CM 10.1 with no problems!
[Nook Color General] don_ernesto:
yep, i'm having lots of FCs now, and i'm preatty convinced it is because my trascend class 6, i will also try with a sandisk,

now a doubt, at some moment it was told that 16GB cards werent any good for running an OS, is this true? should i stay in the 8GB?
[Nook Color General] pixeljunk:
If it makes you feel any better, I've got a Transcend 8GB class 6 and it has been flawless. Nearly a week of running CM7 without a single force close or need to reboot.

Now, the battery life of CM7 is another story! :)
[Nook Color General] don_ernesto:
i was running also flawlessly for a couple of weeks, but maybe a week ago i began having lots of FC problems. tried reflashing from the begining the verygreen image and still have the problems. today i was going to flash an older version of CM7, what version are you running?
[Nook Color General] byelims:
Yes, the abiliity of 4kb read/write is really important when running a system on a sd card. So is it for SSD.
[Nook Color General] robot8:
Just a follow up post. It's been a week since I changed over to a CL4/8G Sandisk, and my Nook has had not a single FC since. Not one. Updated to latest CM7 stable and overclocked to 1.3Ghz on this card. Smooth, zippy and getting Linpack scores of 16 mflops with Quadrant over 2800. One happy camper here :D

Sandisk C4/8G	Transcend C6/8G
R	W	R	W (MB/s)
Seq	6.973	4.905	17.30	18.16
Rand 4KB/QD=32	2.816	[B][COLOR="Red"]1.259[/COLOR][/B]	3.513	0.018
[Nook Color General] pixeljunk:
Running the "stable" version. Haven't done any nightly updates.
[Nook Color General] Tnexus:
Well this explains why my card sucks...

-----------------------------------------------------------------------

Patriot 16GB Class 10:

Sequential Read: 20.747 MB/s

Sequential Write: 16.899 MB/s

Random Read 4KB (QD=32): 5.070 MB/s

Random Write 4KB (QD=32): 0.014 MB/s
[Nook Color General] case-sensitive:
I just installed CM7.02 on a 16G sandisk class 4 and it's been running just fine. I did have loads of problems running customized froyo with 8G class 6 cards by transscend and by patriot (but no problem with 8G class 2 sandisk). YMMV.
[Nook Color General] stormjumper:
(Almost) everyone seems to be using CrystalDiskMark.

Does anyone have any suggestions for a on-device app?

(I found something called Disk Benchmark, but it doesn't seem to do differentiate random writes in the results.)
[Nook Color General] byronczimmer:
Read this after buying a small handful of Transcend 8GB/6 cards.

How do I test each individual card to see what its specs are?

And I may have to hit Costco and get a few cheap ones as well.
[Nook Color General] byronczimmer:
So is it common wisdom now (based on this thread) that the stat to care about is the Random Write speed, which is what applications would need for small updates to their personal databases, etc?
[Nook Color General] chinly43:
This is hopefully going to be the best thread I've ever read here at xda. I tested my current sdcard and saw a HORRIBLE write speed where it counted, so I looked into the best-performing cards and found the 16GB class 4 SanDisk had the highest marks at a site that compiled people's results.

Anyway, said card was on sale for $25 at Radioshack, so I picked one up. Here are the benchmarks I'm getting, running 5x100MB tests. Hopefully the awesome results mean improved performance.

NEW SanDisk 16GB Class 4

Sequential Read : 10.609 MB/s
Sequential Write : 5.853 MB/s
Random Read 512KB : 10.616 MB/s
Random Write 512KB : 1.125 MB/s
Random Read 4KB (QD=1) : 3.379 MB/s [ 825.0 IOPS]
Random Write 4KB (QD=1) : 1.453 MB/s [ 354.7 IOPS]
Random Read 4KB (QD=32) : 2.970 MB/s [ 725.1 IOPS]
Random Write 4KB (QD=32) : 1.257 MB/s [ 306.9 IOPS]

Test : 100 MB [F: 0.0% (0.0/14.8 GB)] (x5)
Date : 2011/05/03 21:50:47
OS : Windows 7 SP1 [6.1 Build 7601] (x64)

Lexar 8GB Class 4 (from 10 days ago)

Sequential Read : 16.184 MB/s
Sequential Write : 8.222 MB/s
Random Read 512KB : 16.371 MB/s
Random Write 512KB : 1.174 MB/s
Random Read 4KB (QD=1) : 6.273 MB/s [ 1531.6 IOPS]
Random Write 4KB (QD=1) : 0.010 MB/s [ 2.4 IOPS]
Random Read 4KB (QD=32) : 7.382 MB/s [ 1802.2 IOPS]
Random Write 4KB (QD=32) : 0.011 MB/s [ 2.6 IOPS]

Test : 100 MB [H: 9.0% (10.4/115.8 MB)] (x5)
Date : 2011/05/03 22:20:44
OS : Windows 7 SP1 [6.1 Build 7601] (x64)

SanDisk 8GB Class 2 (from December, with T-Mobile G2)

Sequential Read : 13.029 MB/s
Sequential Write : 5.677 MB/s
Random Read 512KB : 12.550 MB/s
Random Write 512KB : 3.268 MB/s
Random Read 4KB (QD=1) : 1.054 MB/s [ 257.3 IOPS]
Random Write 4KB (QD=1) : 0.621 MB/s [ 151.7 IOPS]
Random Read 4KB (QD=32) : 0.462 MB/s [ 112.7 IOPS]
Random Write 4KB (QD=32) : 0.616 MB/s [ 150.4 IOPS]

Test : 100 MB [F: 68.0% (5152.0/7572.0 MB)] (x5)
Date : 2011/05/03 22:40:53
OS : Windows 7 SP1 [6.1 Build 7601] (x64)

Ancient unclassified SanDisk 1GB (supplied with pre-retail G1)

Sequential Read : 11.732 MB/s
Sequential Write : 4.876 MB/s
Random Read 512KB : 11.656 MB/s
Random Write 512KB : 2.189 MB/s
Random Read 4KB (QD=1) : 4.759 MB/s [ 1161.9 IOPS]
Random Write 4KB (QD=1) : 0.030 MB/s [ 7.2 IOPS]
Random Read 4KB (QD=32) : 4.774 MB/s [ 1165.6 IOPS]
Random Write 4KB (QD=32) : 0.029 MB/s [ 7.0 IOPS]

Test : 100 MB [F: 9.2% (88.8/968.3 MB)] (x3)
Date : 2011/05/05 12:18:49
OS : Windows 7 SP1 [6.1 Build 7601] (x64)
[Nook Color General] GTT1:
Can someone explain the important info from the above stats that effect using the card for running CM7 on a NC

I am assuming from reading this thread at the beginning that it is this Random Write 4KB (QD=32) : 1.257 MB/s.

Is their anyway to get this info on a card you are interested in before you buy it and can we be sure that all cards when tested provide the same reads/writes when in a NC.
[Nook Color General] chinly43:
1) It's the small-block random write speed (which is the 4KB one), but I don't know which queue depth is important, 1 or 32. The OP didn't explain why they used 32, so I included both.

2) I can't say for sure, because I don't know very much about it, but it would seem that the small block speed is important because when running apps and such from the card, it's relatively rare that huge chunks of data will need to be written/read all at once (which is what the card class speed measures), but common that little bits of data will need to go back and forth.

3) There are a few more speeds listed here, I didn't look that hard for others though - http://forums.whirlpool.net.au/archive/1582172
[Nook Color General] a.fenderson:
You duplicated one of these to the other, they're exact matches.
[Nook Color General] Garoto1973:
Hi Compa!

Where can I buy a Sandisk class 2 or 4 in Costa Rica that's not a "robo". My NC is arriving on Sunday and I can't wait for a SD in the mail!

I also have a Patriot Class 4 in my phone. I might try to use it for the Nook. Are Patriots class 4 ok for SD boot?
[Nook Color General] chinly43:
Thanks for catching that, I must have failed to copy the last results. I'll take it off the post until I can run it again later. It was super slow anyway.

EDIT: I only ran x3, not x5, but the results are there again.
[Nook Color General] a.fenderson:
No problem. I've got 5 SanDisk cards on the way from Amazon (1GB, 2GB, 4GB, 8GB, 2x16GB), so I'll bench them and post my logs as well.
[Nook Color General] jacorso:
Personally looking forward to this.
[Nook Color General] robot8:
The crucial bit is how fast the card does small block random writes.

No way to tell on the card or packaging. Even the same cards from the same brand may perform differently. The speeds vary from batch to batch. No way to tell until you actually benchmark it. YMMV.

FWIW, I'd avoid Class 6 and higher cards as they are optimized for high speed sequential r/w and generally perform well on small block random reads but poorly for writes. You will probably get better results from most Class 2 or Class 4 cards.

After a couple of weeks pulling my hair out due to random FCs and blaming the Nook/CM7/OC kernel/apps, I realized the problem was due to the SD cards, at first I could not believe it as I was using expensive Class 6 and 10 "performance" cards. Well, they may perform well for shooting and viewing videos, but they sure suck when running an OS.

I now have zero problems since the switch and swear by Class 4/8G Sandisks. :D
[Nook Color General] LBN1:
I am using a Kingston Class 4 16gb, but also have a slow random write result as most others have posted.

For those that have changed to a Sandisk card, when you run Quadrant does it still take a long time (1-2minutes) to get past the I/O write test? Whenever I run Quadrant it takes a long time at that point of the test and I am wondering if this is related. Quadrant does finish and I end up with around 1700 scores, but it is somewhat annoying when it seems to hang for a couple of minutes.
[Nook Color General] swoozle:
No particular reason. The results were similar in showing a large difference compared to other cards so I didn't see the need to show both queue depths.

I suppose if we see big differences in performance versus queue depth for a certain card, we can explore that effect as well.
[Nook Color General] chinly43:
I haven't noticed any abnormal quadrant times. Runs in about the same amount of time as it does on my G2. Score just now was 1500.
[Nook Color General] hoteladriano:
Anecdotal evidence at best, but I haven't experienced any FC problems or stalled market downloads in cm7 7.0.2 stable since switching from the 8gb c6 Transcend to the 8gb c4 Sandisk.

I have been using Pulse as much as possible on the Sandisk, as that was the app that constantly gave my build on the Transcend card problems. So far, it seems to be completely stable on the Sandisk.

The overall performance feels fairly responsive. No (unexpected) lag anywhere to be found.

It's worth noting that the Sandisk cards are on sale at Radioshack now. The website says that they are class 2 cards, but in store they are selling the class 4 cards at the same, discounted price ($15).
[Nook Color General] a.fenderson:
The SanDisk 16GB class 2 cards are actually on sale right now at "most stores" (Radio Shack) for only $24.99, which is about as cheap as I've found anywhere online. My 2x 16GB Sandisk class 2 cards from Amazon (seller: eTECH) were delivered today, so I'll try to post benchmarks for those tonight.

Here's the link to the 8GB for $14.99 at Radio Shack.
[Nook Color General] don_ernesto:
tuanis mae??!!

i don't know, i bought mine at Amazon, i am sooo disappointed with the offer of technology here that i almost forgot there are stores here
[Nook Color General] Taosaur:
I picked up one of the 16GB Sandisks from Radioshack (no class listed, so probably 2), and I haven't benchmarked it, but CM7.0.2 is both faster and more stable from the card than stock OS from the eMMC. I was planning boot-from-SD as a stepping stone, but I think I'll leave everything right where it is :)
[Nook Color General] robot8:
I can concur. While I had random issues here and there, Pulse was the one app I could guarantee getting a FC with. Pulse was constantly giving FCs when I was using a Transcend Class 6/8G.

I can pretty much assume that a good way to check an SD card is to see how well or not it runs Pulse. :cool:
[Nook Color General] robot8:
Can't use your Quadrant scores for a comparison if you don't state what speed you're running your Nook at. I run overclocked at 1.3Ghz and first run of Quadrant on boot will average 2400+. Second and subsequent runs can get me an average of 2800 but I don't think those are reliable scores (due to caching?).

As to be expected, always a little slower when it gets to the I/O tests. Compared to the other tests, it does feel like it's taking a longer time but definitely NOT 1-2 minutes long on my Sandisk.
[Nook Color General] Taosaur:
At first glance, the 32GB Transcend looks very serviceable as a CM7 boot drive. If you decide to use verygreen's size-agnostic image on it, let us know how it performs.
[Nook Color General] akay56:
I have been fooling around with the 'J disk benchmark' on the Optimus one. This app can benchmark both emmc and uSd. And it has 4kb r/w testing, although I don't know whether that is the same as random r/w. And I actually got the uSd faster than emmc! This may be in line with a poster in this thread who said that he found the performance while booting from uSd snapier than stock on emmc.
[Nook Color General] LBN1:
I've been running at 300/1.1Ghz with Interactive governor; As an example, when doing Quadrant on my Nook and while waiting for it to finish the I/O write test, I have been able do an entire Quadrant test on my Nexus One, before the Nook has finished that one part of the test! Just got a 16gb Sandisk, so I will see soon if that makes a difference and will post the results.
[Nook Color General] dohturdima:
Heads up, Staples has Sandisk Class 4 8gb uSD card on sale for $20 plus tax. I purchased a Transcend Class 6 prior to that but haven't opened it and will probably send it back. Verygreen's CM7 ran terribly on Patriot Class 10 4gb, slow and many fcs.
[Nook Color General] noblerinthemind:
Was using PNY 4gb class 4 with terrible results - FC, terrible internet. Just bought 8gb 4C Sandisk at Radioshack - 14.99 + tax. Can't wait to try it out. Wish I had read this thread before. I just gave up and went back to stock 1.2.

Thanks OP and contributors!
[Nook Color General] ExploreMN:
I wish I had read this thread about 5 hours ago... Bought a 16gb Class 10 Patriot card...running that CrystalDiskMark program...

..................Read......Write

4k..............2.68.......0.010

4kQ32........2.74..........0.018

I wish I could swear right now...but I think the amount of swearing would make a mod delete my account or something. :( At $4.00 a gallon I have to spend half the cost of the card just to return/exchange it!
[Nook Color General] a.fenderson:
On the plus side, if you decide to run from the eMMC, that'll make a really good data card. :)
[Nook Color General] angomy:
Well, I bought a Sandisk 16GB class 4 card to replace my Transcend 8GB class 6 for a CM7 SD install and so far have had many FCs and weird things happening.

Running diagnostics via Easeus to see if the card is borked (after I noticed having issues with it, I wiped and re-imaged it with fresh downloads of CM7 etc).

Maybe you'll be luckier; Radioshack is having a (pre) Mom's Day special where their Sandisk cards are half off so I only paid $25 for the 16GB card.

When I tried downloading CrystalDiskMark, I got a warning message from antivirus that it had spyware in the archive so I deleted it.. maybe I'm downloading from the wrong place?
[Nook Color General] a.fenderson:
Are you downloading CrystalDiskMark from the developer's site? If not, try that. I'm running Avast and it didn't report any problems with the file during download, or just now when I explicitly scanned the installer file--what antivirus program are you using? During the install, it does ask you to allow it to install PC Matic and Real Player, but you can opt out of both of these.
[Nook Color General] angomy:
Ah, I checked the site you linked and I guess I didn't read it carefully enough -- the installer comes bundled with OpenCandy which is runs ads. My antivirus reads it as adware so pops up a warning sign. I'd rather not install that so I'll find something else to benchmark the card with :x
[Nook Color General] a.fenderson:
Gotcha, but FYI, opencandy only makes the recommendation to install another app or two during installation of CrystalDiskMark. I'm not a fan of adware, but to me, this really doesn't fit the definition--if you choose not to install the recommended software, opencandy doesn't install itself to your system, run ads when using CrystalDiskMark, or anything like that. It does send anonymous info during the install process of the main app, but if you opt out of the recommended installs, that's it. See the FAQ here, especially the bits about what it does and does not do if you opt out.